Field of the Invention
The present invention relates to a method of manufacturing a photoelectric conversion device.
Description of the Related Art
Japanese Patent Laid-Open No. 8-236534 discloses a technique of forming a plasma nitride film without performing an H2 sinter process after forming the uppermost layer Al wiring, and then performing annealing. Japanese Patent Laid-Open No. 8-236534 also discloses a technique of forming a plasma oxide film without performing the H2 sinter process after forming the uppermost layer Al wiring, then further forming a plasma nitride film by applying SOG, and performing annealing after that. Japanese Patent Laid-Open No. 8-236534 further discloses a technique of performing the H2 sinter process after forming the uppermost layer Al wiring, and performing annealing after forming a PSG film and a plasma nitride film sequentially. Note that Japanese Patent Laid-Open No. 8-236534 is not directed to the manufacture of a photoelectric conversion device or a solid-state image sensor.
In a field of the photoelectric conversion device such as a CMOS image sensor or a CCD image sensor, various efforts are being made to reduce a dark output (dark current). The dark output is a signal generated even though the photoelectric conversion device is not exposed to light.
As a method of reducing the dark output, for example, a method of forming a silicon nitride film after forming the uppermost wiring layer, and then performing annealing in a hydrogen containing atmosphere or a method of performing annealing in the hydrogen containing atmosphere after forming the uppermost wiring layer and before forming an insulating film such as a silicon oxide film is considered. However, such a method is insufficient to reduce the dark output.